<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * A KeyCache which streams to and from disk.
 *
 * @package    Swift
 * @subpackage KeyCache
 * @author     Chris Corbyn
 */
class Swift_KeyCache_DiskKeyCache implements Swift_KeyCache
{
	/** Signal to place pointer at start of file */
	const POSITION_START = 0;

	/** Signal to place pointer at end of file */
	const POSITION_END = 1;

	/** Signal to leave pointer in whatever position it currently is */
	const POSITION_CURRENT = 2;

	/**
	 * An InputStream for cloning.
	 *
	 * @var Swift_KeyCache_KeyCacheInputStream
	 */
	private $_stream;

	/**
	 * A path to write to.
	 *
	 * @var string
	 */
	private $_path;

	/**
	 * Stored keys.
	 *
	 * @var array
	 */
	private $_keys = array();

	/**
	 * Will be true if magic_quotes_runtime is turned on.
	 *
	 * @var boolean
	 */
	private $_quotes = false;

	/**
	 * Create a new DiskKeyCache with the given $stream for cloning to make
	 * InputByteStreams, and the given $path to save to.
	 *
	 * @param Swift_KeyCache_KeyCacheInputStream $stream
	 * @param string $path to save to
	 */
	public function __construct(Swift_KeyCache_KeyCacheInputStream $stream, $path)
	{
		$this->_stream = $stream;
		$this->_path = $path;

		if (function_exists('get_magic_quotes_runtime') && @get_magic_quotes_runtime() == 1) {
			$this->_quotes = true;
		}
	}

	/**
	 * Set a string into the cache under $itemKey for the namespace $nsKey.
	 *
	 * @see MODE_WRITE, MODE_APPEND
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param string $string
	 * @param integer $mode
	 *
	 * @throws Swift_IoException
	 */
	public function setString($nsKey, $itemKey, $string, $mode)
	{
		$this->_prepareCache($nsKey);
		switch ($mode) {
			case self::MODE_WRITE:
				$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_START);
				break;
			case self::MODE_APPEND:
				$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_END);
				break;
			default:
				throw new Swift_SwiftException(
					'Invalid mode [' . $mode . '] used to set nsKey=' .
					$nsKey . ', itemKey=' . $itemKey
				);
				break;
		}
		fwrite($fp, $string);
		$this->_freeHandle($nsKey, $itemKey);
	}

	/**
	 * Set a ByteStream into the cache under $itemKey for the namespace $nsKey.
	 *
	 * @see MODE_WRITE, MODE_APPEND
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_OutputByteStream $os
	 * @param integer $mode
	 *
	 * @throws Swift_IoException
	 */
	public function importFromByteStream($nsKey, $itemKey, Swift_OutputByteStream $os, $mode)
	{
		$this->_prepareCache($nsKey);
		switch ($mode) {
			case self::MODE_WRITE:
				$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_START);
				break;
			case self::MODE_APPEND:
				$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_END);
				break;
			default:
				throw new Swift_SwiftException(
					'Invalid mode [' . $mode . '] used to set nsKey=' .
					$nsKey . ', itemKey=' . $itemKey
				);
				break;
		}
		while (false !== $bytes = $os->read(8192)) {
			fwrite($fp, $bytes);
		}
		$this->_freeHandle($nsKey, $itemKey);
	}

	/**
	 * Provides a ByteStream which when written to, writes data to $itemKey.
	 *
	 * NOTE: The stream will always write in append mode.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_InputByteStream $writeThrough
	 *
	 * @return Swift_InputByteStream
	 */
	public function getInputByteStream($nsKey, $itemKey, Swift_InputByteStream $writeThrough = null)
	{
		$is = clone $this->_stream;
		$is->setKeyCache($this);
		$is->setNsKey($nsKey);
		$is->setItemKey($itemKey);
		if (isset($writeThrough)) {
			$is->setWriteThroughStream($writeThrough);
		}

		return $is;
	}

	/**
	 * Get data back out of the cache as a string.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 *
	 * @return string
	 *
	 * @throws Swift_IoException
	 */
	public function getString($nsKey, $itemKey)
	{
		$this->_prepareCache($nsKey);
		if ($this->hasKey($nsKey, $itemKey)) {
			$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_START);
			if ($this->_quotes) {
				ini_set('magic_quotes_runtime', 0);
			}
			$str = '';
			while (!feof($fp) && false !== $bytes = fread($fp, 8192)) {
				$str .= $bytes;
			}
			if ($this->_quotes) {
				ini_set('magic_quotes_runtime', 1);
			}
			$this->_freeHandle($nsKey, $itemKey);

			return $str;
		}
	}

	/**
	 * Get data back out of the cache as a ByteStream.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_InputByteStream $is to write the data to
	 */
	public function exportToByteStream($nsKey, $itemKey, Swift_InputByteStream $is)
	{
		if ($this->hasKey($nsKey, $itemKey)) {
			$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_START);
			if ($this->_quotes) {
				ini_set('magic_quotes_runtime', 0);
			}
			while (!feof($fp) && false !== $bytes = fread($fp, 8192)) {
				$is->write($bytes);
			}
			if ($this->_quotes) {
				ini_set('magic_quotes_runtime', 1);
			}
			$this->_freeHandle($nsKey, $itemKey);
		}
	}

	/**
	 * Check if the given $itemKey exists in the namespace $nsKey.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 *
	 * @return boolean
	 */
	public function hasKey($nsKey, $itemKey)
	{
		return is_file($this->_path . '/' . $nsKey . '/' . $itemKey);
	}

	/**
	 * Clear data for $itemKey in the namespace $nsKey if it exists.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 */
	public function clearKey($nsKey, $itemKey)
	{
		if ($this->hasKey($nsKey, $itemKey)) {
			$this->_freeHandle($nsKey, $itemKey);
			unlink($this->_path . '/' . $nsKey . '/' . $itemKey);
		}
	}

	/**
	 * Clear all data in the namespace $nsKey if it exists.
	 *
	 * @param string $nsKey
	 */
	public function clearAll($nsKey)
	{
		if (array_key_exists($nsKey, $this->_keys)) {
			foreach ($this->_keys[$nsKey] as $itemKey => $null) {
				$this->clearKey($nsKey, $itemKey);
			}
			if (is_dir($this->_path . '/' . $nsKey)) {
				rmdir($this->_path . '/' . $nsKey);
			}
			unset($this->_keys[$nsKey]);
		}
	}

	// -- Private methods

	/**
	 * Initialize the namespace of $nsKey if needed.
	 *
	 * @param string $nsKey
	 */
	private function _prepareCache($nsKey)
	{
		$cacheDir = $this->_path . '/' . $nsKey;
		if (!is_dir($cacheDir)) {
			if (!mkdir($cacheDir)) {
				throw new Swift_IoException('Failed to create cache directory ' . $cacheDir);
			}
			$this->_keys[$nsKey] = array();
		}
	}

	/**
	 * Get a file handle on the cache item.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param integer $position
	 *
	 * @return resource
	 */
	private function _getHandle($nsKey, $itemKey, $position)
	{
		if (!isset($this->_keys[$nsKey][$itemKey])) {
			$openMode = $this->hasKey($nsKey, $itemKey)
				? 'r+b'
				: 'w+b';
			$fp = fopen($this->_path . '/' . $nsKey . '/' . $itemKey, $openMode);
			$this->_keys[$nsKey][$itemKey] = $fp;
		}
		if (self::POSITION_START == $position) {
			fseek($this->_keys[$nsKey][$itemKey], 0, SEEK_SET);
		} elseif (self::POSITION_END == $position) {
			fseek($this->_keys[$nsKey][$itemKey], 0, SEEK_END);
		}

		return $this->_keys[$nsKey][$itemKey];
	}

	private function _freeHandle($nsKey, $itemKey)
	{
		$fp = $this->_getHandle($nsKey, $itemKey, self::POSITION_CURRENT);
		fclose($fp);
		$this->_keys[$nsKey][$itemKey] = null;
	}

	/**
	 * Destructor.
	 */
	public function __destruct()
	{
		foreach ($this->_keys as $nsKey => $null) {
			$this->clearAll($nsKey);
		}
	}
}
